GE AF-650 GP Series, Design And Installation Manual

Page: 70 / 166

The following parameters are relevant for the Speed Control:
Parameter Description of function
PI-00 Speed PID Feedback Source Select from which input the speed PID should get its feedback.
PI-02 Speed PID Proportional
Gain
The higher the value, the quicker the control. However, too high value may lead to oscillations.
PI-03 Speed PID Integral Time Eliminates steady state speed error. Lower value means quick reaction. However, too high value may
lead to oscillations.
PI-04 Speed PID Differentiation
Time
Provides a gain proportional to the rate of change of the feedback. A setting of zero disables the
differentiator.
PI-05 Speed PID Diff. Gain Limit If there are quick changes in reference or feedback in a given application - which means that the error
changes swiftly - the differentiator may soon become too dominant. This is because it reacts to
changes in the error. The quicker the error changes, the stronger the differentiator gain is. The differ-
entiator gain can thus be limited to allow setting of the reasonable differentiation time for slow
changes and a suitably quick gain for quick changes.
PI-06 Speed PID Lowpass Filter
Time
A low-pass filter that dampens oscillations on the feedback signal and improves steady state
performance. However, a filter time that is too long will deteriorate the dynamic performance of the
speed PID control.
Practical settings of parameter PI-06 taken from the number of pulses per revolution on from encoder
(PPR):
Encoder PPR PI-06 Speed PID Lowpass Filter Time
512 10 ms
1024 5 ms
2048 2 ms
4096 1 ms
Table 6.16
The following must be programmed in order shown (see
explanation of settings in the Programming Guide)
In the list, it is assumed that all other parameters and
switches remain at their default setting.
Function Parameter Setting
1) Make sure the motor runs properly. Do the following:
Set the motor parameters using nameplate data P-02 to P-07
F-04 & F-05
As specified by motor nameplate
Have the adjustable frequency drive makes an auto tune P-04 Auto Tune [1] Enable complete auto tune
2) Check the motor is running and the encoder is attached properly. Do the following:
Press the “Hand” keypad key. Make sure the motor is
running and note in which direction it is turning
(henceforth referred to as the “positive direction”).
Set a positive reference.
Go to DR-20 Motor Angle . Turn the motor slowly in the
positive direction. It must be turned so slowly (only a
few RPM) that it can be determined if the value in
DR-20 Motor Angle is increasing or decreasing.
DR-20 Motor Angle N.A. (read-only parameter) Note: An increasing value
overflows at 65,535 and starts again at 0.
If DR-20 Motor Angle is decreasing, then change the
encoder direction in E-81 Term 32/33 Encoder Direction .
E-81 Term 32/33
Encoder Direction
[1] Counter clockwise (if DR-20 Motor Angle is decreasing)
3) Make sure the drive limits are set to safe values
Set acceptable limits for the references. F-52 Minimum
Reference
F-53 Maximum
Reference
0 RPM
1,500 RPM
Application Setup Examples AF-650 GP
TM
Design and Installation Guide
DET-767A 6-15
6 6